Synthesis and Characterization of Polylactic Acid/ Polymethyl Methacrylate/silica Biodegradable Nanocomposite

In this study, biodegradable nanocomposites were developed by blending polylactic acid (PLA) with polymethyl methacrylate (PMMA) and incorporating stearic acid-modified silica nanoparticles (SiO₂) to enhance thermal and mechanical properties. PMMA was synthesized via emulsion polymerization. PLA/PMMA/SiO₂ nanocomposites were then prepared using in-situ and solution blending methods with varying PLA:PMMA ratios (30:70, 50:50, 70:30 wt%) and SiO₂ contents (0, 2, 5, 10 wt%). The nanocomposite surface morphology was analyzed using scanning electron microscopy (SEM) and light microscopy. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to characterize the thermal behavior, and mechanical properties were evaluated via Shore-D hardness test and tensile test. Biodegradability was assessed through both biodegradation and enzymatic degradation tests. For the biodegradation study, samples were buried in cactus and humus soil, monitoring weight loss as an indicator of biodegradability. Microscopic imaging was used to analyze the structural changes that occurred before and after soil exposure. The results showed that, in both degradation methods, higher SiO₂ content led to an increased weight loss percentage. The incorporation of SiO₂ accelerated the biodegradation of PLA.